Melatonin Could One Day Treat Multiple Sclerosis

The chances for a relapse of multiple sclerosis are different at different times of the year. Seasonal changes in disease activity may be related to sunlight exposure and the body’s production of the hormone melatonin, researchers say.

Multiple sclerosis (MS) flare ups are caused by changes in melatonin levels in the spring and summer seasons, according to findings published in Cell.

Researchers from Brigham and Women’s Hospital in Boston, Massachusetts studied 139 patients with relapsing remitting MS in order to determine the relationship between seasonal changes in disease activity in MS and melatonin levels. The investigators examined improvement in symptoms and seasonal factors as proposed links to MS disease activities, such as vitamin D levels, UV incidence, and upper respiratory tract infections.

“We wanted to see what environmental factors would reveal to us about this disease,” study leader Francisco Quintana, PhD, from the Ann Romney Center for Neurologic Diseases, explained in a press release. “We knew that MS disease activity changed with the seasons. What we’ve uncovered offers an explanation for why that is the case.”

The researchers determined melatonin was the key factor consistently linked to severity of MS disease activity. Levels of melatonin are higher during longer days in the spring and summer and lower in the shorter fall and winter days. This theory was tested in mice and human cell models, and the researchers determined that melatonin affected pathogenic T cells that attack and destroy regulatory T cells (which are the mechanism that keeps the pathogenic T cells in line). “We found that melatonin has a protective effect,” continued Quintana. “It dampens the immune response and helps keep the bad guys – or pathogenic T cells – at bay.”